#include <bits/stdc++.h>
using namespace std;
struct ListNode {
	int val;
	ListNode *next;
	ListNode() : val(0), next(nullptr) {}
	ListNode(int x) : val(x), next(nullptr) {}
	ListNode(int x, ListNode *next) : val(x), next(next) {}
};
class Solution {
public:
	ListNode* removeNthFromEnd(ListNode* head, int n) {
		ListNode* dummyHead = new ListNode(); dummyHead->next = head;
		ListNode* fast = dummyHead;
		ListNode* slow = dummyHead;
		while(n-- && fast != NULL){
			fast = fast->next;
		}
		fast = fast->next;
		while(fast != NULL){
			fast = fast->next;
			slow = slow->next;
		}
		ListNode* tmp = slow->next;
		slow->next = slow->next->next;
		delete tmp;
		
		return dummyHead->next;
	}
};


int main(){
	
	return 0;
}
